双能X射线透射系统的噪声分析与滤波方法研究

Noise analysis and filtering methods of dual energy X-ray transmission system

针对原始双能X射线透射信号包含的噪声复杂且滤波困难的问题,根据双能X射线透射分选技术的工作原理,建立了双能X射线透射信号采集与分析系统,对双能X射线透射信号中所包含的背景噪声、孤立噪声、电路互连串扰噪声和探测随机噪声的来源及其特性进行了研究;对探测随机噪声的高斯分布特性、孤立噪声的无规律性和探测板之间的串扰噪声的固定性进行了归纳,提出了一种改进的邻域相关自适应中值滤波法,进行了6009铝合金块的双能X射线透射分析实验,对比分析了中值滤波法和所提出算法的滤波效果。研究结果表明,所提出的改进的邻域相关自适应中值滤波法能有效地滤除双能X射线透射信号中的噪声。

Aiming at the problem that the noise of the original dual-energy X-ray transmission signal is very complicated and difficult to filter,the dual-energy X-ray transmission signal acquisition and analysis system was established based on the operational principle of dual-energy Xray transmission separation technology. The sources and characteristics of background noise,isolated noise,circuit interconnect crosstalk noise and detection random noise contained in the original dual-energy X-ray transmission signal were studied. The Gauss distribution of detection random noise,irregularity of isolated noise and the fixity of crosstalk noise between detection boards were researched,a new improved adaptive median filtering method based on the statistic of the neighborhood pixels was proposed. Dual-energy X-ray transmission analysis experiment was tested on 6009 aluminum alloy block,the filtering effect of median filtering method and the proposed method was analyzed comparatively. The results indicate that the noise in the original dual-energy X-ray transmission signal can be effectively filtered by the improved adaptive median filtering method.